Lafari@lemmy.world to No Stupid Questions@lemmy.world · 8 months agoIs "If A then B" equal to "B if and only if A"?message-squaremessage-square40fedilinkarrow-up138arrow-down110
arrow-up128arrow-down1message-squareIs "If A then B" equal to "B if and only if A"?Lafari@lemmy.world to No Stupid Questions@lemmy.world · 8 months agomessage-square40fedilink
minus-squareEp1cFac3pa1m@lemmy.worldlinkfedilinkarrow-up19arrow-down1·edit-28 months agoIf Nazi, then fascist = true Fascist, if and only Nazi = not true If car, then vehicle = true Vehicle if and only if car = not true
minus-squareValmond@lemmy.mindoki.comlinkfedilinkarrow-up3·8 months agoI used the bananas are fruits analog but your one works well too!
minus-squareEp1cFac3pa1m@lemmy.worldlinkfedilinkarrow-up5·8 months agoI just figured with Lemmy’s interest in politics it seemed like an obvious example. I threw in the car because I didn’t want to be that guy who makes everything about nazis…
minus-squareBoinkage@lemmy.worldlinkfedilinkarrow-up2·8 months agoYeah careful with that, the logic example Nazis will be all over you if you don’t mix it up some.
minus-squareEp1cFac3pa1m@lemmy.worldlinkfedilinkarrow-up3·8 months agoNot everything is about Nazis, Boinkage, geez…
minus-squareLafari@lemmy.worldOPlinkfedilinkarrow-up1·8 months agoIf car, then vehicle = true Car if and only if vehicle = true. Is this correct? Therefore “If A then B” = “A if and only if B” (or “If B then A” = “B if and only if A”)?
minus-squarezenharbinger@lemmy.worldlinkfedilinkarrow-up6·edit-28 months agoB can still be true when a is false. iff means that b can only be true when a is true. Also, the equivalent statement is. vehicle if and only if car. not car only if vehicle since a truck is a vehicle, the statement is false. Somewhat wrong above: A B a iff b T T T T F F F T F F F T look online for truth tables.
If Nazi, then fascist = true
Fascist, if and only Nazi = not true
If car, then vehicle = true
Vehicle if and only if car = not true
I used the bananas are fruits analog but your one works well too!
I just figured with Lemmy’s interest in politics it seemed like an obvious example. I threw in the car because I didn’t want to be that guy who makes everything about nazis…
Yeah careful with that, the logic example Nazis will be all over you if you don’t mix it up some.
Not everything is about Nazis, Boinkage, geez…
If car, then vehicle = true
Car if and only if vehicle = true.
Is this correct?
Therefore “If A then B” = “A if and only if B” (or “If B then A” = “B if and only if A”)?
B can still be true when a is false. iff means that b can only be true when a is true.
Also, the equivalent statement is.
vehicle if and only if car.
not
car only if vehicle
since a truck is a vehicle, the statement is false.
Somewhat wrong above:
A B a iff b
T T T
T F F
F T F
F F T
look online for truth tables.